1. Field of the Invention
The present invention relates to a reactor for reforming a liquid fuel, and more particularly to a reactor for generating hydrogen to be supplied to a fuel cell and an electronic device equipped with such a reactor.
2. Description of the Related Art
In recent years, fuel cells are being used as clean power sources having high energy conversion efficiency in, for example, motor vehicles and mobile devices. A fuel cell of this type is a device that causes an electrochemical reaction between a fuel and oxygen in the atmosphere, thereby to directly obtain electric energy from chemical energy.
While a hydrogen monomer can be used as a fuel for use in the fuel cell, a problem arises in handling the hydrogen monomer because the hydrogen monomer is a gas at the ambient temperature and pressure. Approaches also are known in which hydrogen is stored by using a hydrogen storage alloy. The approaches, however, have a problem in that the storage amount of hydrogen per unit volume is small, so that the approaches are insufficient as power-source fuel storage means of, particularly, small electronic apparatuses such as cellular electronic devices. In comparison, in reforming fuel cells of the type that generates power by using hydrogen obtainable by reforming a liquid fuel containing hydrogen atoms, such as alcohols, the fuel can easily be stored in the form of liquid, and the amount of hydrogen per unit volume of the fuel is relatively large. For using fuel cells of this type, cases take place that require a vaporizer for vaporizing the liquid fuel, a reformer for extracting hydrogen necessary for power generation by causing the reaction between the liquid fuel and high temperature water vapor, a carbon monoxide removing unit for removing carbon monoxide that is a by-product of the reforming reaction, and the like (see Jpn. Pat. Appln. KOKAI Publication No. 2002-356310, for example).
In the disclosed technique, an optimal operation temperature range of the vaporizer and/or the carbon monoxide removing unit is different from an optimal operation temperature range of the reformer, therefore making it difficult to produce temperature differences across the different temperature ranges.
Further, several pipes have to be coupled to the vaporizer, the reformer, and the carbon monoxide removing unit to perform processes, such as supply of the fuel and/or oxygen, and discharging of hydrogen. In this case, heat of the vaporizer, the reformer, and the carbon monoxide removing unit transfers as it is to the outside through the pipes, thereby causing significant heat losses.
Further, the carbon monoxide removing unit and the reformer are interconnected through the pipes or flow pathways through which the reformed fuel and the like flow. In particular, in a case where the carbon monoxide removing unit and the reformer are interconnected through the respective coupling pipes corresponding to a plurality of flow pathways, the reformer and the carbon monoxide removing unit are different from each other in the amount of expansion depending on the temperature difference. Consequently, excessive stresses may impose on connection portions, consequently leading to damage in the connection portions.